College Physics 10th Edition by Raymond Serway,Chris Vuille

Exercise 18

A lens made of glass ( n g = 1.52) is coated with a thin film of MgF 2 ( n s = 1.38) of thickness t. Visible light is incident normally on the coated lens as in Figure P24.30. (a) For what minimum value of t will the reflected light of wavelength 540 nm (in air) be missing (b) Are there other values of t that will minimize the reflected light at this wavelength Explain.